Two speed gear box for e-cargo bicycles?

Discussions related to motors other than hub motors.
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Hugh-Jassman   1 kW

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Two speed gear box for e-cargo bicycles?

Post by Hugh-Jassman » Sep 21 2015 12:42pm

Has anyone made something like this, but lighter weight?

I need one that will handle 1500 watts of torque thrust. Geared down to 18mph
This thread shows one for a motor cycle but nothing comes up for a bicycle.
https://endless-sphere.com/forums/viewt ... ox#p221255

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Miles   100 GW

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Re: Two speed gear box for e-cargo bicycles?

Post by Miles » Sep 21 2015 2:09pm

What's "1500 Watts of torque thrust" ???

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Hugh-Jassman   1 kW

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Re: Two speed gear box for e-cargo bicycles?

Post by Hugh-Jassman » Sep 24 2015 3:29pm

Torque, moment, or moment of force (see the terminology below) is the tendency of a force to rotate an object about an axis,[1] fulcrum, or pivot. Just as a force is a push or a pull, a torque can be thought of as a twist to an object. Mathematically, torque is defined as the cross product of the lever-arm distance vector and the force vector, which tends to produce rotation.

Loosely speaking, torque is a measure of the turning force on an object such as a bolt or a flywheel. For example, pushing or pulling the handle of a wrench connected to a nut or bolt produces a torque (turning force) that loosens or tightens the nut or bolt.

Thrust is a reaction force described quantitatively by Newton's second and third laws. When a system expels or accelerates mass in one direction, the accelerated mass will cause a force of equal magnitude but opposite direction on that system.[1] The force applied on a surface in a direction perpendicular or normal to the surface is called thrust. Force, and thus thrust, is measured in the International System of Units (SI) as the newton (symbol: N), and represents the amount needed to accelerate 1 kilogram of mass at the rate of 1 metre per second squared.

torque is not the correct term, but thrust by it's self is not descriptive enough.


I just want to see a larger picture of E-Motion's avatar picture. or the finished gear box from the thread above. it should be listed on the Wiki, but I don't see it. seems like this should be available as a simple factory made device by now.

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Re: Two speed gear box for e-cargo bicycles?

Post by spinningmagnets » Sep 24 2015 3:36pm

Ft/lbs or newton/meters are the traditional measurements of torque that is measured at the rear wheel (I probably wrote them wrong). An inefficient system (like a small-diameter rear direct-drive hubmotor) will convert much of the 1500W of input into heat instead of torque. A geared hubmotor of the same diameter and width will have close to 5 times the wheel-torque per input watts. A mid drive that gives the motor the use of the bikes gears can have a dramatic torque-multiplication between the input watts and output torque at the wheel (especially in the lowest gear).

Thud produced a 2-speed, but he only made a few, and he hasn't made one for quite a while.

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Miles   100 GW

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Re: Two speed gear box for e-cargo bicycles?

Post by Miles » Sep 24 2015 4:04pm

Sure, I know what torque is, I know what thrust is and I know what power is : )

The point I was trying to make is that you haven't quantified anything........

Torque is what we need to know to specify a gearbox. As Ron said, the SI unit is the newton-metre.

Simply, multiply motor torque by reduction ratio to gearbox. Or, work back from the maximum load....

I have a design for a 2 speed gearbox. I'm not sure if there's much of a need though, so I've been concentrating on motors, which there's definitely a need for..... Anyway, it could be specified to handle up to around 40 Nm input torque with direct drive and 2:1 output. It won't be $30 on ebay, though...

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Re: Two speed gear box for e-cargo bicycles?

Post by Hugh-Jassman » Sep 25 2015 3:53pm

maybe all the post a bout gears that I have been reading is out dated by now. I defiantly would like to find a way around using a gear box. please give me a link to more info???? there needs to be an article about how and why to program controllers. especially the new more complex ones.

I think the Nuvinci would be good for 1000 watt out put if acceleration is not extreme??

I found pages about building a gear box http://www.thepixelpump.com/widdershins ... ission.php
http://www.instructables.com/id/Making- ... m-Gearbox/ and videos:https://www.youtube.com/watch?v=Ver7yDgc6-8

then I finally found this one.... seems a bit large https://endless-sphere.com/forums/viewt ... p?p=327720 https://endless-sphere.com/forums/viewt ... 28&t=13731
google works better than any other search engine....
Miles wrote: I have a design for a 2 speed gearbox. I'm not sure if there's much of a need though, so I've been concentrating on motors, which there's definitely a need for..... Anyway, it could be specified to handle up to around 40 Nm input torque with direct drive and 2:1 output. It won't be $30 on ebay, though...
Last edited by Hugh-Jassman on Sep 25 2015 4:40pm, edited 2 times in total.

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Re: Two speed gear box for e-cargo bicycles?

Post by SlowCo » Sep 25 2015 3:59pm

Why do you (think you) need a two speed gearbox?

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Re: Two speed gear box for e-cargo bicycles?

Post by Hugh-Jassman » Sep 25 2015 4:04pm

With gears you can move the "efficiency peak" around to match your mph. On a

fixed hub motor you are permanently tied to your power-band and this presents a real problem at low speeds. Low mph/rpm on a hub motor places you into the low efficiency areas of the power-band. You can compensate a little if you have an ammeter and are really careful about using even less current than the current limit allows (so you are using almost no voltage down low in order to be more efficient) but you are still fighting a less than desirable situation



At 10 mph the efficiency is running about 50%. The good efficiency areas don't even exist until you are past 20 mph. So unlike with gears where you can "gas it" off the line and be in the good efficiency areas all the time, hub motors have a real "issue" with quick starting. Quick starts on a hub motor are really bad news for battery usage... (much worse than if you are geared right).


Tell me why I do not need one. 1000 watts will move 400lbs up an 8% grade at about 13mph. that's too low of gear to drive around in all day.

SlowCo wrote:Why do you (think you) need a two speed gearbox?

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Chalo   100 GW

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Re: Two speed gear box for e-cargo bicycles?

Post by Chalo » Sep 25 2015 4:14pm

If you know gross wattage, wheel diameter, and road speed, then torque can be extrapolated.

The key here is using a shafted motor with multiple reduction or a hub motor with chain reduction, geared to provide a free speed of about 20 mph. That should provide close to 18 mph under normal riding loads, and will yield maximum power at about 10 mph. There should be no need for a second gear.
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Re: Two speed gear box for e-cargo bicycles?

Post by Hugh-Jassman » Sep 25 2015 4:43pm

the state of washigton limits the out put for a bicycle to 1000 watts. that is only enough to drive 400lbs total combined weight up an 8% grade at about 13mpg. it would take a 1500 watt out put to do about 20mpg under same conditions. that is a moped under washington state law.

this would be ok if your not worried about the lawyers of the jerks that blame you for their mistakes. just use a larger motor.

and of coarse if you want to sell the bikes legally , you must make them according to the law.

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Re: Two speed gear box for e-cargo bicycles?

Post by SlowCo » Sep 25 2015 4:55pm

Hugh-Jassman wrote:the state of washigton limits the out put for a bicycle to 1000 watts. that is only enough to drive 400lbs total combined weight up an 8% grade at about 13mpg. it would take a 1500 watt out put to do about 20mpg under same conditions. that is a moped under washington state law.

this would be ok if your not worried about the lawyers of the jerks that blame you for their mistakes. just use a larger motor.
In your opening post you mentioned 1500W and in this last reply I gather you would like to stay <1000W? Wouldn't the upcoming Bafang BBS-HD 1000W kit be a good solution then?:
https://endless-sphere.com/forums/viewt ... 0&start=50
In combination with a (very) good MTB chain and gear cluster it should give you the reductions you need.

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Re: Two speed gear box for e-cargo bicycles?

Post by Chalo » Sep 25 2015 9:34pm

SlowCo wrote:Wouldn't the upcoming Bafang BBS-HD 1000W kit be a good solution then?:
https://endless-sphere.com/forums/viewt ... 0&start=50
In combination with a (very) good MTB chain and gear cluster it should give you the reductions you need.
That had better be a 6- or 7-speed MTB drivetrain, because an up-to-date 9- or 10- (or 11-speed) system is going to gargle its giblets when you add that kind of steady power. My own 9-speed bike can't take what I'm dishing out at the pedals, no power assist.
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Re: Two speed gear box for e-cargo bicycles?

Post by spinningmagnets » Sep 26 2015 6:54am

I agree with Chalo. There are riders who are experiencing very accelerated drivetrain wear on their 750W BBS02, when unrestricted and running 1,000W. Chains and sprockets breaking after a short amount of time that have been beaten into submission. In my view, the 1,000W BBSHD (capable of 1500W?) will have the benefit of being able to take 50V X 20A = 1,000W continuous without overheating, even on a fairly hot day.

The benefit of the extra wattage capability (IMHO) is for a fully loaded longtail cargobike on a steep uphill with two bags of groceries and a toddler in the baby seat. A 750W would have to downshift more due to heat, the BBSHD could take the hill in a higher gear and at a higher speed. If you are using your BBS02 or BBSHD to pop wheelies, stock up on sprockets and chains.

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Re: Two speed gear box for e-cargo bicycles?

Post by docnjoj » Sep 26 2015 9:23am

Um.....How about a Xiongda 2 speed motor? Low is real powerful and hi is great up to about 21-22 mph with 44 volt lipo.
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Re: Two speed gear box for e-cargo bicycles?

Post by ferret » Sep 26 2015 10:07am

Don't believe everything you think.

Cove GNG-Spot build thread

Astral Rune build thread

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Re: Two speed gear box for e-cargo bicycles?

Post by Hugh-Jassman » Sep 26 2015 1:16pm

Does the Bafang BBS-HD 1000W kit drive the cranks? I want to get a way from that.

I M ALSO THINKING HOW EASY IT WOULD BE TO ADD UP THE TOTAL COMBINED WEIGHT TO 450LBS.


SlowCo wrote:
In your opening post you mentioned 1500W and in this last reply I gather you would like to stay <1000W? Wouldn't the upcoming Bafang BBS-HD 1000W kit be a good solution then?:
https://endless-sphere.com/forums/viewt ... 0&start=50
In combination with a (very) good MTB chain and gear cluster it should give you the reductions you need.

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Re: Two speed gear box for e-cargo bicycles?

Post by Hugh-Jassman » Sep 26 2015 1:41pm

this is great.....thanks for the links.

I have been thinking that if there is a way around using a gear box, the secret maybe found in the new controllers as well as new motors? So I hope some one can write an article about how to program the new controllers.

I really like the Lightning rods new high speed high voltage motor. I do not know what it is capable of. and I expect I would need different gears on it.

is this gear box reviewed on endless sphere?
ferret wrote:You can try one of these:

http://www.andymark.com/Transmissions-s/202.htm


Avner.
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Re: Two speed gear box for e-cargo bicycles?

Post by Hugh-Jassman » Sep 26 2015 1:45pm

Please tell me more about the Xiongda 2 speed motor, it sounds interesting. does it have two speed and nothing in-between? or is there a trick with the controller going on there, for hill climbing high torque??

docnjoj wrote:Um.....How about a Xiongda 2 speed motor? Low is real powerful and hi is great up to about 21-22 mph with 44 volt lipo.
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Re: Two speed gear box for e-cargo bicycles?

Post by SlowCo » Sep 26 2015 3:28pm

Hugh-Jassman wrote:Please tell me more about the Xiongda 2 speed motor, it sounds interesting. does it have two speed and nothing in-between? or is there a trick with the controller going on there, for hill climbing high torque??

docnjoj wrote:Um.....How about a Xiongda 2 speed motor? Low is real powerful and hi is great up to about 21-22 mph with 44 volt lipo.
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Re: Two speed gear box for e-cargo bicycles?

Post by John in CR » Sep 30 2015 11:03pm

The way around an efficiency robbing, reliability reducing, maintenance and weight increasing gearbox is to instead invest that money and weight, is the right size motor and gear it properly. Locomotives driven by electric motors don't have multi-speed gearboxes. Telsa engineers initially thought the same as you and tried to make the Roadster a 2 speed and learned better after wasting millions, so now Tesla's are single speeds. Brammo uses or used them on their consumer emoto's, but more to give potential customers something familiar than out of need as riders generally use just one gear, but their racing emoto is a single speed like all the other electric racers.
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Re: Two speed gear box for e-cargo bicycles?

Post by Punx0r » Oct 01 2015 3:24am

Hugh-Jassman wrote:the state of washigton limits the out put for a bicycle to 1000 watts. that is only enough to drive 400lbs total combined weight up an 8% grade at about 13mpg. it would take a 1500 watt out put to do about 20mpg under same conditions. that is a moped under washington state law.
Sounds well suited to the example Chalo gave with a 1000W motor yielding maximum power at ~10mph? That should also be legal for you.

Remember that motor controllers are buck converters - at low speeds they trade voltage for current, so can take a modest power (watts) input and convert it to a lot of torque (current) at low speeds.

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Re: Two speed gear box for e-cargo bicycles?

Post by Hugh-Jassman » Oct 05 2015 2:04pm

why is it so hard to find things on this endless sphere?

I found this photo once but not again....

Image

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Re: Two speed gear box for e-cargo bicycles?

Post by Miles » Oct 05 2015 2:31pm

Hugh-Jassman wrote:....I found this photo once but not again....
https://endless-sphere.com/forums/viewt ... 28&t=22525

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Re: Two speed gear box for e-cargo bicycles?

Post by Thud » Oct 05 2015 2:38pm

Hugh-Jassman wrote:why is it so hard to find things on this endless sphere?

I found this photo once but not again....

Image
not a photo...its a rendering.
get some......

All information & advice provided by Thud are "Open Source" & free for personal use & distribution under the following agreement linked below.
http://creativecommons.org/licenses/by-nc-nd/3.0/

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